Squalamine, 3.beta.-(N-[3-aminopropyl]-1,4-butanediamine)-7.alpha.,24.zeta.-dihydroxy- 5.alpha.-cholestane 24-sulfate, is an aminosterol that has been isolated from the dogfish shark, Squalus acanthias. See K. Moore, S. Wehrli, H. Roder, M. Rogers, J. Forrest, D. McCrimmon, and M. Zasloff, Proc. Nat. Acad. Sci. (USA), Vol. 90, February 1993, 1354-1358. See also U.S. Pat. No. 5,192,756 to Zasloff et al.
This water-soluble steroid exhibits potent bactericidal activity against both gram-positive and gram-negative bacteria. In addition, squalamine is antifungal and exhibits lytic activity against protozoa. The molecule was initially recovered as a natural product through extraction of several tissues of the dogfish shark, including the stomach, liver, gallbladder and spleen. Its structure was determined by fast atom bombardment mass spectroscopy and NMR spectroscopy (S. Wehrli et al., Steroids 58, 1993, 370-378). The chemical structure of squalamine is that of a cationic steroid characterized by a condensation of an anionic bile salt intermediate with spermidine. Squalamine represented the first example of asteroid to which spermidine is covalently coupled and a new class of antibiotics (K. Moore, S. Wehrli, H. Roder, M. Rogers, J. Forrest, D. McCrimmon, and M. Zasloff, Proc Nat. Aced. Sci. (USA), Vol. 90, February 1993, 1354-1358).